The present invention relates broadly to a test set for the Sarcalm system and in particular to a delay line null command generator test set for testing the operation of the Sarcalm system.
The Synthetic Array Radar Command Air Launched Missile otherwise known as Sarcalm, (SARCALM), is designed to deliver a missile to a ground target located on a synthetic array radar map. The synthetic array radar comprises a coherent transmitter and receiver, a synthetic array processor and display, and a velocity sensor and motion compensation computer. The function of the velocity sensor and motion compensation computer is to focus the map for the length of a synthetic array. The target is located on the map in the time-frequency coordinates. The SARCALM system guides the missile to a point whose time-frequency coordinates match those of the target.
The purpose of the null command generator test set is to verify the actual operating conditions of the null command generator which is in the Sarcalm system.
The null command generator in the Sarcalm system obtains beam pointing information from a syntetic array radar return signal which has the monopulse pattern of the receiving antenna superimposed on it. A number of schemes have been proposed for the null command generator, each with alternate hardware mechanization; the null command generator test set of the subject invention is capable of testing all of them. A previously proposed Sarcalm null command generator test set utilizes a bank of ganged potentiometers for the generation of the monopulse difference pattern of the antenna. Each potentiometer modifies the signal from a single oscillator representing a single doppler line. Such a hardware implementation severely restricts the test signals which can be employed. Furthermore, it can only simulate a single "snapshot" of the input signal to the Sarcalm system at a time. The present invention operates with aggregate test signals and, therefore, can accommodate any spectral input including replays of tape recordings taken during actual test flights. The capability of testing the performance of the null command generator with signals which were generated by typical real targets provides pseudo operational test results.